Inkjet printers generally operate by ejecting ink onto media, such as paper. One type of inkjet printer utilizes stationary staggered inkjet pens, which are also more generally referred to as fluid ejector assemblies. The inkjet pens are immobile, and are arranged in a staggered fashion over one axis referred to as the inkjet pen axis. Media is moved past the assemblies along another axis, referred to as the media axis, which is perpendicular to the inkjet pen axis. As the media moves past the inkjet pens, the pens accordingly eject ink onto the media. This type of inkjet printer is customarily, but not necessarily, used in industrial settings that require fast printing performance.
The inkjet pens can be or become misaligned in two ways. Along the inkjet pen axis, the inkjet pens may not be aligned correctly, leading to gaps between output from adjacent pens, or leading to overlapping output from adjacent pens. Along the media axis, too, the inkjet pens may not be aligned correctly. Because the pens are staggered, such misalignment may result from the fluid ejection delays of the inkjet pens not being properly set with respect to one another. An inkjet pen may thus begin outputting ink too soon or too late, resulting in misalignment along the media axis.
A method of one embodiment of the invention reduces misalignment of a pair of staggered fluid ejector assemblies positioned along a first axis perpendicular to a second axis along which media moves past the assemblies. The method reduces misalignment of the pair of staggered fluid ejector assemblies along the first axis. Fluid bands are output by different series of nozzles of each assembly. The method then selects as a series of active nozzles of each assembly one of the different series of nozzles outputting one of the fluid bands that is substantially aligned with one of the fluid bands output by the other assembly.